Backlighting for computer keyboard

ABSTRACT

Embodiments of a peripheral backlighting system for keyboards are shown and described, which include one or more light-emitting panels exterior to the keyswitches of the keyboard. The panels are preferably electroluminescent material and surround at least two sides, and preferably all sides, of the stem of a keyswitch or the space in which the stem slides up and down during use. Alternatively, the electroluminescent panel(s) may extend substantially continuously between and underneath a plurality of keyswitches. The panels extend closely adjacent to the stem or stem path, or under the keyswitch, to be as far under the key cap as possible without extending into the stem or cap of the keyswitch. The EL panels are preferably powered by the computer keyboard port, via voltage inverters. Preferably, the keyswitch is translucent or partially translucent, and the base plate over the EL panels, if any, is at least partially translucent or transparent. This way, the light from the light-emitting panels radiates upward through, and preferably around the outer surface of, the translucent keycaps, rather than up through an aperture or lightpipe in the center of the keycaps.

DESCRIPTION

This national application filed under 35 U.S.C. 371 claims priority ofPCT/US99/27065, filed on Nov. 12, 1999, and U.S. Provisional patentapplication Ser. No. 60/108,310, filed Nov. 13, 1998.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains, in general, to lighting devices for keyswitchassemblies and keyboards, such as computer desktop, laptop, and notebookkeyboards or “Internet-TV” keyboards. More specifically, the inventionrelates to backlighting for keyboards that originates from below thekeys within the keyboard.

2. Related Art

For a long time, keyswitch assembly operators have desired lightedkeyboards and keypads. For example, when an operator is working acomputer keyboard and simultaneously viewing a computer monitor, lowambient light conditions may be preferred, in order to maximize contraston the monitor screen. Also, for example, a portable computer operatormay by necessity be in a low light environment, as when flying in anairplane or riding in a train at night.

In any event, there have been many attempts in the prior art to providelighted keyboards and keypads. Still, many of these attempts have notbeen successful because they result in keyswitch assemblies that are notsufficiently lighted, or lighted in a glaring or distracting manner, orthat are inconvenient, or expensive. Prior attempts at lighted keyboardshave produced fragile systems that consume more power and produce moreheat than is desirable.

Examples of lighted keyswitch assemblies are found in the patentliterature. U.S. Pat. No. 5,801,345 (Mikula-Curtis et al., 1998)discloses LED's attached to the bottom of the printed circuit board(PCB) which emit light that travels up through holes in the PCB and intolight pipes, each of which is received in a key cap to channel the lightup through the interior of the key cap. Also, the Mikula-Curtis et al.system includes a backlighting system with an LED centered under a lightdam and an indicia panel, that emits light up through the center of thearea enclosed by the light dam to back-light the indicia panel.

U.S. Pat. No. 5,612,692 (Dugas et al., 1997) discloses a sealed,LED-lighted keyboard, in which the LEDs are disposed on the printedcircuit board. The LEDs and circuit board are covered by a spacer boardwith openings for allowing electrical contact with the top surface ofthe circuit board and for allowing LED light to reach the upper layersof the system. These “upper layers” include a translucent sealing sheetmembrane with domes, and keys above the domes. Thus, in Dugas, the keysare pushed down to force the domes down so that a conductiveunder-surface of the key may contact the circuit board. The LED lightmust travel up through the spacer board holes, through the center ofeach dome, up through the center of each key, and out the translucentnumber, letter, or other indicia on the top center of the key cap.

U.S. Pat. No. 5,034,602 (Garcia, et al., 1991) discloses a backlightingsystem in which a light emitter, such as an alpha/numeric LED or LCD, isdisposed beneath the center of the key cap or adjacent to a beamsplitter that redirects the light up through the central axis of the keycap.

U.S. Pat. No. 4,806,908 (Krupnik, 1989) discloses a system usingelectroluminescent (EL) strips that extend through registering openingsthat extend transversely through the stems of the key switches in thekeyboard. The EL strips extend from key stem to key stem underneath anopaque, stationary retaining panel being between the keys, so that onlythe key cap is lit only by light that is emitted from the area of the ELstrips inside the key stems (the “internal portion”) and that travels upto the cap of the key. This light from the internal portion of the ELstrip travels up through the center of the clear, transparent, ortranslucent body of the key stem and then to openings or translucentareas in the center of the otherwise opaque key cap. Because the ELstrips run underneath the opaque retaining panel and through openings inthe stems of a plurality of keys, the EL strips are also adapted toprevent withdrawal of the keys from the retaining panel.

Summarily, therefore, conventional backlighting techniques feature meansfor channeling/directing light directly up through the center of the keycap or of the area directly under the indicia panel to be lit. Thisapproach purposely controls the light to travel along a specific centralaxis and then to radiate from the keyboard in a limited area of a singlekey cap or of a single indicia panel. This approach purposely controlsand limits the light path, to prevent light from traveling fromkeyswitch to keyswitch or from shining from the inside of the keyswitchto the outside of the keyswitch.

What is still needed is a durable, economical and effective backlightingsystem for a desktop, laptop, notebook, or “Internet-TV” keyboard. Whatis needed is such a system that supplies appropriate levels of light inthe appropriate areas of the keyboard for enhanced viewing in low/nolight environments.

SUMMARY OF THE INVENTION

The present invention comprises lighting a keyboard for use in low or noambient light environments, by peripherally lighting the keyswitchassemblies on a keyboard or keypad, such as a desktop, laptop, notebook,or Internet-TV keyboard. By “peripherally lighted,” it is meant that thekeyswitch assemblies are lit externally, from outside rather than frominside, preferably from positions substantially circumscribing the sidesand/or extending across the bottom of the keyswitch assemblies. Lightemanates from all or portions of a panel that extends between and/orunderneath a plurality of keyswitches of a keyboard. The panel may be asheet or strip that extends between keyswitches and preferably reachesunderneath the keycaps, by extending near to the stem or stem path of akeyswitch, and/or by extending underneath the keyswitches. Preferably,light emanates up from the radiant panel through the spaces between thekeyswitches, and into and through the keyswitches, to give the selectedportions of the keyboard an overall “glowing” appearance, rather thangiving the keyboard the appearance of having “spots” of light or lightedletters and numerals. This lighting aids key identification and overallvisibility in many low/no light environments, and makes laptop lightingpossible while traveling because of low power consumption.

Preferably, the radiant panel is electroluminescent (EL) materialpositioned above the contact membrane or printed circuit board andgenerally below the keyswitch caps. In embodiments in which the ELmaterial comprises strips or a sheet with perforations, the strip edgesor perforation edges are disposed on at least two sides of, andpreferably entirely or substantially around, the key stem or the spacethrough which the stem travels during depression of the key (“stempath”). In embodiments in which the EL material comprises a continuoussheet of material, the sheet extends generally horizontally underneath aplurality of keyswitches between the contact membrane and the lower-mostextremity of the keyswitch. When a key is depressed, the continuoussheet is impacted by the contact member of the keyswitch, and transfersforce to the contact membrane to execute the “switch.” Thus, at aminimum, the EL material preferably extends underneath the peripheraledges of the key cap, or at a maximum, the EL material extends all theway under the key, either scenario allowing a significant amount oflight to pass into and up through the keyswitches, and preferably alsobetween the spaces between the keyswitches. The panel and EL materialpreferably do not extend into the interior of the key cap or key stem,and do not interfere with operation or removal of the key.

In this and the following Description and Claims, the terms “keyswitchassembly” or “keyswitch” or “key” refer to the device conventionallyprovided in keyboards that is depressed to make contact with and affect(close) its particular switch on the circuit board or membrane (PCB orcontact membrane). A keyswitch is typically made of what is calledherein a “cap” for finger contact and a “key stem” or “stem” which isthe generally vertical structure protruding from the cap toward thecircuit board or membrane and which contacts the board or membrane whenthe key is depressed. Thus, “key stem” herein refers to thedownwardly-protruding post attached to the cap, plus inserts, sleeves,domes, and biasing members that extend around or are otherwise connectedto the post. The cap and stem of a keyswitch may be separate components,or may be a single component plus a biasing member, for example. In theDescription and Claims, the term “substantially continuous panel” meansthat a panel extends without significant apertures or interruptionsexcept for apertures that are used to receive a portion of the keyswitchsuch as the stem or to reach near to the stem but leave a space for thestem path, that is, for the stem to move in and out of the aperture. Theterm “continuous panel” means that the panel extends without significantapertures or interruptions, for example, panels that have no aperturesfor receiving the keyswitch stems. The inventors envision that a singlecontinuous panel would be beneficial in a laptop computer keyboard thatwould have no keyswitch stem apertures but would have a hole through themembrane for receiving a “mouse ball” mechanism, for example. The term“extending between” means that a panel extends from keyswitch tokeyswitch on any number of planes that are near the keyswitches andgenerally parallel to the plane of the keyswitches, and is not intendedto limit the panel location to one particular plane passing through themidpoint of the keyswitches.

One or more panels comprising EL material may be laid down betweenkeyswitches and around the stems or stem paths or underneath thekeyswitches, in one or more areas of the keyboard. The panels may be ofvarious regular or irregular shapes to backlight particular areas of thekeyboard, and the panels may radiate light over all or substantially allof their top surfaces, or may have areas masked or deactivated fromradiating light so that not all of the panel radiates light. Panels areherein described in two general categories, sheets and strips, wherein asheet typically extends between more than two rows of keys and/or morethan two columns of keys, and a strip typically extends between only tworows of keys or between only two columns of keys. Several differentpanels may be provided, for easier design and installation, or for beingseparately-powered for independent on/off or dimming control. Also, ELpanels may be used that provide different colors of backlighting, fordifferentiating different areas of the key board. Also, not all areas ofthe keyboard need to be lit.

Preferably, the keycaps used with the present invention are molded usingtranslucent plastic and have opaque markings or portions on their tops,and the key stems and other parts of the keyswitches are eithertranslucent, transparent, or reflective, so that the keyswitch as awhole tends to transfer or reflect light. Also, the EL material may bepositioned directly underneath a translucent or transparent base platethat is the uppermost portion of the housing of the keyboard.Alternatively, the EL material may be positioned above a base plate, orinstalled without a base plate. This way, because the EL materialpreferably extends across substantially the entire distance betweenkeys, and optionally across the entire distance outside and beneath thekeys, the EL light travels upward through and around the translucentkeycaps and up through the base plate, thereby backlighting selectedportions or substantially the entire top of the keyboard, to “fill” thekeyboard surface with light. Thus, the invented system does not featureonly the interior lighting, that is, the limited, controlled “lightpipe” or axially-channeled light approach discussed in the Related Artsection. Instead, the invented system produces a subtle, overall lightedeffect that yet is not overwhelming or distracting. Having light “glow”from between the keycaps as well as from the keycaps is surprisinglyeffective, and produces a “plane of light” effect, giving the userenough subtle light to see and use the keyboard without having “spots”of light or indicia only lit up on top of the key caps.

The radiant EL panels are preferably powered by the computer keyboardport, via voltage inverters which are commercially available for suchuse. Preferably, one or more dimming, on/off, and auto-off controlsystems are included in the invented system. These controls may be usedto adjust the intensity of the backlighting in some or all portions ofthe backlit keyboard. Also, these controls may be used to automaticallyshut off lighting during extended non-use, for battery conservation, andrestart it when one or more keystrokes are made. In addition, thepreferred controls may be used to independently dim or turn off thelighting of all or selected portions, for example, to produce increaseddifferentiation between the lit portions and the dimmed or non-litportions.

The invented backlighting system allows easier key identification forfewer input errors, for example, for late night use without disruptingsleeping family members and use on airplanes. The invented system allowsa user to accurately and comfortably use the keyboard after purposelydarkening a room to reduce glare and shadows. The overall-lightedkeyboard may reduce eye fatigue that otherwise may occur when constantlymoving the eyes from a lighted monitor to an un-lit keyboard. Theintensity adjustment option gives users the ability to adjust thekeyboard lighting for their own personal comfort and room conditions.

Another objective of the invented system is to provide a durablelighting system that results in a durable and low-maintenance keyboard.The invented system may use conventional, solid keyswitches withouthollow centers, and does not require hollow key stems or specialmodifications to keyswitches, except for the preferred change totranslucent materials. The invented system does not significantlyincrease the temperature of the keyswitches. The invented system doesnot require electronic or other complex connections of lighting membersto the keyswitches. The preferred system therefore provides aneconomical lighting mechanism that does not reduce the reliability andlife of the keyboard.

The invented backlighting system utilizes commercially-availablelighting members, in such a way as to provide a system of efficient,glare-free and low-cost keyboard illumination. The invented system oflighting can be made into any shape of size, for design into newkeyboard assemblies, or retrofitting onto existing keyboards, as will bemore fully described in the detailed specification which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top view of one embodiment of a strip-shapedelectroluminescent (EL) panel, according to the invention.

FIG. 1B is a top view of an embodiment of a die-cut sheet-style EL panelwith rectangular apertures for receiving key stems.

FIG. 1C is a top view of another embodiment of a die-cut sheet-style ELpanel with small circular apertures for receiving key stems.

FIG. 1D is a top view of an embodiment of a continuous sheet-style ELpanel.

FIG. 2 is a top view of a keyboard layout with horizontal rows ofstrip-shaped EL panels beneath and between the keyswitch assemblies.

FIG. 3 is a schematic cutaway side view of an embodiment of theinvention wherein EL panels radiate light up between the keyswitchkeycaps through a translucent base plate and up through the keycaps.

FIG. 4 is a schematic cutaway side view of the embodiment of FIG. 3 withan opaque top housing plate, showing EL panels radiating light upthrough the keycaps only.

FIG. 5 is a schematic cutaway side view of another embodiment of theinvention in which the EL panel extends continuously underneath aplurality of keyswitches.

FIG. 6A is a schematic diagram of a typical EL panel wiring diagram.

FIG. 6B is schematic diagram of an inverter system for one embodiment ofthe invention.

FIG. 7 is an end, cross-sectional view of one embodiment of a desk-topkeyboard, according to the invention, showing a perforated panel of ELmaterial around the key stem assemblies and the collar which supportsthe key stem.

FIG. 8 is an exploded view of the pieces parts of the key board of FIG.7.

FIG. 9 is an end, cross-sectional view of one embodiment of a lap-topkeyboard, according to the invention, showing a perforated panel of ELmaterial around the key stem paths.

FIG. 10 is an exploded view of the pieces parts of the key board of FIG.9.

FIG. 11A is an enlarged view of the key cap of FIGS. 9 and 10.

FIG. 11B is an enlarged view of the hinge of FIGS. 9 and 10.

FIG. 11C is an enlarged view of the rubber actuator of FIGS. 9 and 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the Figures, there are shown several, but not the only,embodiments of the invented backlighting system for keyboard. FIGS. 1A-Cillustrate electroluminescent (EL) panels that may be used in thepresent invention. FIG. 1A is a top view of a strip-shapedelectroluminescent panel 1. FIG. 1B is a top view of a rectangulardie-cut electroluminescent panel 10 with apertures 16 for receiving aplurality of keycaps and stems. FIG. 1C is a top view of a die-cut ELpanel 100 that has small circular apertures 16′ for receiving aplurality of generally cylindrical stems. FIG. 1D is a top view of an ELpanel 1000 that does not require apertures because it extendscontinuously underneath the keyswitches. Panels 1, 10, 100, 1000illuminate homogeneously preferably from their entire top surfaces 2,and connect to a power source at terminals 3, which power source ispreferably the computer keyboard port. Alternatively, other embodimentsmay include masking, deactivation or other construction that results inportions of the top surfaces 2 radiating light and portions notradiating light. For example, the inventors envision embodiments inwhich the panels comprise portions which may not be conventionallyclassified as EL material, or panels which are EL material but aremasked.

Panels 1, 10, 100 are preferably installed by being laid on top of thecontact membrane or other circuit board so that the apertures alignproperly with the areas on the contact membrane corresponding to eachkey. The keyswitch assemblies are inserted into or over the aperturesand, for embodiments with a base plate, the base plate is attached overthe EL panel and around the keys.

The panels 1, 10, 100, 1000 are secured in the keyboard by conventionalmeans, such as being friction fit with one or more members, being a thinmembrane sandwiched between other layers of the keyboard. The ELmaterial may be material commonly referred to as “EL” such as thatavailable from MetroMark, Inc. of Minnetonka, Minn., U.S.A.

FIG. 2 is a top view of a keyboard layout 4 with elongated strip-shapedelectroluminescent panels 1 beneath and between the keycaps 5. Thepanels illuminate substantially the entire keyboard layout 4 andpreferably every keycap 5, due to the effect of the light from thepanels 1 radiating up both between the keycaps and through thetranslucent keycaps 5.

FIGS. 3 and 4 illustrate cutaway side views of a keyboard assemblyincluding discrete keyswitches 9 mounted for contact with printedcircuit board 6. Each keyswitch 9 comprises keycaps 5, and stem 7 whichincludes post 17 and actuating member 27, with at least the cap 5 andpost 17 preferably being translucent or transparent. Electroluminescentpanels are installed on top of the circuit board 6, underneath thekeycaps 5 and beside the stem 7 of each keyswitch. The EL panels, asillustrated, may be either a plurality of strip panels 1 or portions ofone or more sheet panels 10, 100 each having its own electrodes 3 forconnection to a power source. In the case of strip panels 1, the ELmaterial extends close beside the outside surface of stems 7 on at leasttwo sides, and, in the case of sheet panels 10, 100, the EL materialextends closely around the entire outside perimeter or “outer sidesurface 19” of stems 7. With either EL panel style, the EL materialextends under the outer perimeter edge 11 of the keycaps 5, but notinside the keyswitch, and not through any apertures in the stem orkeycaps. This way, as depicted by rays 15, the EL material can radiateup from outside the keyswitch up through the cap, and also into the stemand up through the cap top.

In FIG. 3, a translucent base plate 8 is installed over the panels 1,10, 100, which plate 8 may take the place of the conventional opaquebase plat that forms the top of a conventional keyboard housing. In suchan embodiment, light radiates through from up through the base plate 8,as well as into and up through the keyswitches, to give an overall“glowing” effect to substantial portions of the keyboard.

In FIG. 4, a less preferred, opaque base plate 8′ is installed. In suchan embodiment, the opaque base plate 8′ substantially blocks the lightfrom radiating up between the keyswitches, so that the light travelsonly into and up through the keyswitches. Such alternatives are withinthe scope of the invention, as they still provide substantial lightingto the entire keyswitch and do so by providing the light source aroundthe keyswitches. Additionally, the invention also includes embodimentsin which masking is placed directly on or near the upper surface of theEL panels to mask off selected areas of the EL panels, for example, forspecial design effects desired for artistic reasons or personalpreference.

FIG. 5 illustrates in cutaway view a panel that extends continuouslyunderneath one or more keyswitch assemblies 9′. Such a panel preferablyis entirely or substantially EL material so that it may described as anEL sheet that extends, and radiates, continuously underneath one or morekeyswitch assemblies. Such a continuous sheet therefore needs noperforations for fitting around the key stem or stem path; instead, theEL sheet 1000 extends across the stem path, and the bottom end 21 of thestem that is pushed down during key depression actually contacts andpushes against the sheet 1000 rather than the contact membrane. Thecontact of keyswitch to EL sheet 1000 transfers sufficient force to thecontact membrane 6 to accomplish the keyswitch's task without directcontact between the keyswitch and the contact membrane. Because the ELsheet 1000 extends continuously underneath the keyswitches 9′, the lightrays 15 may shine up through the keyswitch as well as up through thespace between the keyswitches. Alternatively, the inventors envisionthat portions of the EL sheet 1000 shown in FIG. 5 may be masked,deactivated, or made from non-radiating material, as desired foreconomic or aesthetic reasons.

FIG. 6A is a schematic diagram of a typical wiring diagram for oneembodiment of the invented backlighting system. The panels 1 areconnected between a common ground and a high voltage source, such asDC-to-DC converter 13, which converts +5 volts to +100 volts in thisexample. Multiple converters 13 may be applied to drive largerelectroluminescent panels 1, or multiple panels.

FIG. 6b is a schematic diagram of an inverter system for the invention.Other circuitry may be used and other inverter systems may be used,however, the digital inverter consumes less power than conventionaltoroid type inverters and so is preferred. The control system preferablyincludes an auto-off feature, so that the backlighting automaticallyturns off after a set period of un-use of the keyboard. This featurewill extend the life of the battery and the EL material. A listing ofmaterials that may be used for this circuitry follows:

TABLE 1 Schematic Description U/M No in FIG. 6B INVERTER IC - IMP803 1U1 DIODE - 1N4148 BV = 100V 1 D1 VOLUME - 100K 1 VR CHOKE COIL - 68uH 1L1 CHIP CAP 0805 TYPE (+80/−20%) 0.1UF 2 Cbaty, Cs CHIP RESISTOR (0805TYPE) +/− 10% 2K 1 Rel 2M 1 Rel 750K 1 Rsw EL “LAMP” 1 EL LAMP

FIGS. 7 and 8 illustrate a particularly preferred embodiment of thepresent invention, a desktop keyboard 200 with the invented backlightingsystem. EL sheet(s) 100 are installed to place their apertures 16′snapped around the key collars 103 of the keyboard housing 105, whichcollars 103 surround the stems 104 of the keyswitch assemblies 106. Theapertures 16′ preferably have diameters the same as the outer diametersof the collars 103 for frictional engagement of the EL sheet 100 withthe collar and so that the EL sheets 100 extend as near as possible tothe outside surface of the stems 104. The stems 104, which comprise cap110, contact insert 112, and actuator 114 as shown disassembled in FIG.8. The contact inserts 112 slide down in the collars 103 when the key isdepressed for contact the contact membrane 120. Membrane 120 is receivedwithin the bottom cabinet 122 of the keyboard 200 and cooperates withPCB and connector 121. After a key is released, the insert then slidesback up to its original position as biased by the actuator 114. Thiskeyboard 200 does not include masking or any base plate on top of the ELsheets 100, and preferably the contact insert 112, cap 110 aretranslucent. Therefore, the EL sheets 100 radiate light up between thekeycaps 110, and also up through the cap 110 and through the top portionof the contact insert 112. Optionally, the key collars 103 may betranslucent, which further allows light from the sheets 100 to passthrough the collars 103, into the insert 112, and then up through thecap 110.

As shown to best advantage in FIG. 8, assembly of preferred embodiment200 is convenient and economical because of the shape and position ofthe EL sheets 100. The EL material does not interfere with any movingparts and is received in a spaces which are not used for other purpose.As shown in FIG. 8, several different sheets 100 may be installed invarious different areas of the keyboard, for example, smaller sheetsunder the function keys, larger sheets under the letter keys, and mediumsheets under the numeric keypad. FIG. 8 illustrates one possiblelocation for light intensity control and knob 123, but various locationsmay be appropriate for different keyboards. As described above, controlsfor independent on/off and adjustment of intensity may be included foreach or some of the sheets, and may be designed from conventionaltechnology. Also, various light colors may be used, or the sheets may beformed in other that rectangular shapes for personal taste or “designer”appeal.

FIGS. 9 and 10 illustrate another especially-preferred embodiment, thatis, a laptop keyboard 300. This keyboard 300 includes transparent keycaps 310, transparent hinges 311, transparent rubber actuators 312(biasing members), contact insert 313, transparent base plate 314,contact membrane 120, and metal mounting bracket 316. EL sheet 100 withsmall round apertures 16′ is positioned between and generally parallelto the contact membrane 120 and the base plate 314. Apertures 16′ arepositioned directly below holes in the base plate 314 which arepositioned directly below the actuators 312 and the center of the keycaps 310. Thus, the actuators 312, baseplate holes, and apertures 16′are all axially aligned, to define the “stem path 324” in which the“stem” travels, wherein the “stem” in this keyboard design may beconsidered the actuator 312 and insert 313. Thus, the edge 326 of the ELmaterial, defining the aperture 16′, extends to be at or near the stempath. In other words, the EL material preferably extends as far aspossible under the key cap 310, without entering into any hole orpassage in the keyswitch or into the interior of the keyswitch, withoutbeing centered under the cap, and without “light piping” to direct thelight up to the center of the cap. This way, the EL “lamp” shines upfrom the outside of the keyswitch into a substantial portion of the capand preferably through the hinge to illuminate the key. Also, the EL“lamp” shines up through the plate 314 to provide an appropriately-litbackground around the keys. Because the stroke of the laptop keyboardkeys is shorter than that in a desktop keyboard, the EL materialdelivers an adequate light output even from beneath the bottom of theclear base plate 314, and from beneath the transparent hinges 311.

As shown to best advantage in FIG. 10, assembly of keyboard 300 isefficient and convenient, because of the approach of installing the ELpanel 100 as a thin, planar sheet parallel to and in between alreadyexisting planar members of the keyboard. Enlargements of several of thepieces parts of keyboard 300 are shown in FIGS. 1A-C for clarity.

The nature and position of the EL material in the preferred embodimentsalso provides the benefit of increased resistence to liquid spills.Having a continuous or near-continuous panel of the EL materialextending between and/or under the keyswitches blocks liquid andmoisture from reaching the PCB/contact membrane.

Various materials may be used for the parts of the invented system. Forexample, transparent key caps may be ABS or P.C. plastic; transparenthinges may be nylon or P.C.; transparent or semi-transparent “rubber”actuators may be silicone rubber, Latex, or rubber; transparent or whitecontact inserts may be POM or nylon; transparent base plates may be ABSor P.C., and lower housing members may be metal or plastic. Othermaterials may be chosen for the desired translucency and/or color, withdurability of the material as a main objective.

The invented keyboard lighting system, with its many possibilities fordifferent colors, patterns of light, and light adjustments, may bedesigned for the many individual tastes and needs of people in themarket. The invented system offers advantages for young people whodesire a stylish keyboard, senior or visually-impaired citizens who needhelp reading the keyboard, or others who are tired of the conventionalcomputer look.

The invention that has been described is effective in providingillumination of a keyboard or different types of keyswitch assemblies,for example, many keyswitch assemblies made with conventional materialsby conventional techniques. An important object of the present inventionis to provide effective backlighting to keyboards and keyswitches ofconventional design, rather than requiring significant redesign ofkeyboards and keyswitches.

Although this invention has been described above with reference toparticular means, materials and embodiments, it is to be understood thatthe invention is not limited to these disclosed particulars, but extendsinstead to all equivalents within the scope of the following claims.

What is claimed is:
 1. A backlit keyboard for use with a computer orinternet television, the keyboard comprising: a plurality of keyswitchescomprising caps having a translucent or transparent portion and stemsdepending from the caps; a substantially planar panel of light-emittingelectroluminescent material extending beneath a plurality of said caps,wherein the panel is entirely outside of the keyswitches; and atranslucent or transparent base plate received below the caps and abovesaid panel; wherein said panel emits light directly up through saidtranslucent or transparent base plate and into said keyswitches andthrough said translucent or transparent portion.
 2. A backlit keyboardas in claim 1, wherein the panel of light-emitting electroluminescentmaterial is powered by a computer power source with voltage increased bymeans of a voltage inverter.
 3. The keyboard as in claim 1, wherein thepanel is an electroluminescent membrane.
 4. The keyboard as in claim 1,wherein the caps are substantially translucent or transparent.
 5. Thekeyboard as in claim 1, wherein the stems are substantially translucentor transparent.
 6. The keyboard as in claim 1, wherein the keyswitchesare substantially translucent or transparent.
 7. The keyboard as inclaim 1, wherein the keyboard further comprises hinges locatedunderneath the caps, wherein at least one of said hinges issubstantially translucent or transparent.
 8. The keyboard as in claim 1,wherein the panel emits light up between the caps.
 9. The keyboard as inclaim 1, further comprising opaque masking between at least some of thekeyswitches for blocking light from the panel from emitting up betweenthe caps.
 10. The keyboard as in claim 1, wherein portions of the panelbetween some of the plurality of keyswitches are made from non-radiatingmaterial to limit light from radiating up between the caps of said someof the plurality of keyswitches.
 11. The keyboard as in claim 1, whereinthe panel is continuous between and underneath said plurality ofkeyswitches and has no perforations for keyswitches.
 12. The keyboard asin claim 1, wherein the keyboard further comprises hinges underneath thecaps, wherein at least one of said hinges is substantially translucentor transparent nylon.
 13. The keyboard as in claim 1, wherein the stemseach have an outer side surface, and the panel has one or moreperforations and a perforation edge defining each perforation, whereinthe panel receives the stems in the perforations and the perforationedge extends near to the stem outer side surface for emitting lightthrough the keyswitches.
 14. The keyboard as in claim 13, wherein thepanel is an electroluminescent membrane.
 15. The keyboard as in claim13, wherein the caps are substantially translucent or transparent. 16.The keyboard as in claim 13, wherein the stems are substantiallytranslucent or transparent.
 17. The keyboard as in claim 13, wherein thekeyswitches are substantially translucent or transparent.
 18. Thekeyboard as in claim 13, wherein the keyboard further comprises hingesunderneath the caps, wherein at least one of the hinges is substantiallytranslucent or transparent.
 19. The keyboard as in claim 1, wherein: thekeyboard further comprises a circuit board or membrane generallyparallel to and below said panel; the stems have bottom ends; the panelhas one or more perforations and a perforation edge defining eachperforation, and the panel is located substantially between thekeyswitches and the circuit board or membrane, the perforations aredirectly below the stem bottom ends for receiving the stem bottom endswhen the keyswitches are depressed to contact the circuit board ormembrane.
 20. The keyboard as in claim 19, wherein portions of the panelbetween some of the plurality of keyswitches are made from non-radiatingmaterial to limit light from radiating up between the caps of said someof the plurality of keyswitches.
 21. The keyboard as in claim 19,wherein the panel is an electroluminescent membrane.
 22. The keyboard asin claim 19, wherein the caps are substantially translucent ortransparent.
 23. The keyboard as in claim 19, wherein the stems aresubstantially translucent or transparent.
 24. The keyboard as in claim19, wherein the keyswitches are substantially translucent ortransparent.
 25. The keyboard as in claim 19, wherein the keyboardfurther comprises hinges underneath the caps, wherein at least one ofthe hinges is substantially translucent or transparent.
 26. The keyboardas in claim 1, wherein: the keyboard further comprises a circuit boardor membrane generally parallel to and below said panel; the stems havebottom ends; the panel is continuous and is located between thekeyswitches and the circuit board or membrane so that, when thekeyswitch is depressed, the keyswitch contacts the panel to applypressure to the circuit board or membrane.
 27. A backlit keyboard foruse with a computer or internet television, the keyboard comprising: aplurality of keyswitches comprising caps having a translucent ortransparent portion and stems depending from the caps; and asubstantially planar panel of light-emitting electroluminescent materialextending beneath a plurality of said caps, wherein the stem do notextend through the panel; wherein said panel emits light into saidkeyswitches and through said translucent or transparent portion; andwherein the keyboard does not include any base plate above the panel oflight-emitting electroluminescent material.
 28. A backlit keyboard as inclaim 27, wherein the keyboard does not include any masking on saidpanel.
 29. A backlit keyboard as in claim 27, wherein the panel oflight-emitting electroluminescent material is powered by a computerpower source with voltage increased by means of a voltage inverter. 30.A backlit keyboard as in claim 27, wherein the panel is anelectroluminescent membrane.
 31. The keyboard as in claim 27, whereinthe caps are substantially translucent or transparent.
 32. The keyboardas in claim 27, wherein the stems are substantially translucent ortransparent.
 33. The keyboard as in claim 27, wherein the keyswitchesare substantially translucent or transparent.
 34. The keyboard as inclaim 27, wherein the keyboard further comprises hinges underneath thecaps, wherein at least one of the hinges is substantially translucent ortransparent.
 35. The keyboard as in claim 27, wherein the keyboardfurther comprises hinges underneath the caps, wherein at least one ofsaid hinges is substantially translucent or transparent nylon.
 36. Thekeyboard as in claim 27, wherein portions of the panel between some ofthe plurality of keyswitches are made from non-radiating material tolimit light from radiating up between the caps of said some of theplurality of keyswitches.
 37. The keyboard as in claim 27, wherein thestems each have an outer side surface, and the panel has one or moreperforation and a perforation edge defining each perforation, whereinthe panel receives the stems in the perforations and the perforationedge extends near to the stem outer side surface for emitting lightthrough the keyswitches.